KTFM (Killing the Fine Manual)

In a recent newgroup thread, someone was looking for a shell
equivalent to "killpg" (a system call that sends a signal to
a process group). Someone who really should
have known better answered with one word: "kill". The
original poster shortly replied with something like "Gee, I
didn't know I could use anything but PID's with kill"
and got another laconic response: " Read the man page."

And of course he had, though not carefully. The syntax for specifying
a process group rather than a pid is to prefix the process group
number with a "-" (or "--" so you can leave out the signal itself
for the default kill).

However, that's not the whole story. Shells like bash
override kill with their own function, which has different syntax
and options. So someone who had read "man kill" but not the kill
section in "man bash" could be further confused. Looky here,
for example:

If you ask "Should we be in space?" you ask a nonsense question. We are in space. We will be in space. (Frank Herbert)

Show me your flowchart and conceal your tables, and I shall continue to be mystified. Show me your tables, and I won't usually need your flowchart; it'll be obvious. (Fred Brooks, The Mythical Man Month)